May 10, 2009

Medical Devices Blog (clever name!) has a couple posts on solvent bonding of polycarbonate, something which composes the bulk of the happy medical device company's assembly, well that and PVC tubing to polycarbonate fittings (see the well done descriptive picture). He is using cyclohexanone to bond the polycarbonate and getting 20 lbf tensile strength. This seems about right to me depending on geometry, and is industry standard for this type of bonding. We took efforts to design out most of the polycarbonate to polycarbonate bonds out by designing custom molded parts, which saves on assembly time and gives a superior product. If the cyclohexanone is still tacky after 18 hours you're probably using too much cyclohexanone.

We use a couple different solvent dispensors (one from Ventrex) and fixtures to get the application right and ran a few quick studies to determine the ideal amount to apply. Ventrex may be able to help you out with your application, this is one thing I enjoy and think I do well at- letting vendors do the bulk of work for me.

Also industry standard is the ETO sterilization with polycarbonate. At a previous company we tried to gamma sterilize Polycarbonate and that doesn't work well, the fittings became brittle and discolored to varying degrees- that didn't stop us from using them though...

Update, yeah I screwed up the title originally, that should be polycarbonate to polycarbonate.

4 comments:

I used to be a design and manufacturing engineer, and now I run a website called Industrial Interface that is is focussed on helping engineers in the medical device industry. It's a great tool for solving specific applications like this solvent bonding issue.

The system allows engineers, designers, and sourcing professionals to post design problems and sourcing needs to our website. Industrial Interface then matches those projects with industrial suppliers who have worked on similar projects in the past, or who have experience with similar technologies. The system finds potentially relevant suppliers by allowing Engineers to post as little as a problem statement and some technical details.

I'd love to talk to the owner of this blog about how Industrial Interface can help your readers.

This is a very interesting blog you have. I run a forum called medical device guru which has daily updates on emerging medical device technology that you might find interesting. I also have a blog at http://legacymedsearch.wordpress.com/which gives career advice for people in (or looking to get it) the medical device field that I would like to link to you.

I have a question: if I am solvent bonding using cyclohexanone and I want to check for biocompatibility on the assembly, how would that work? If the solvent dries, do we still need to check for biocompatibility of the solvent?